Cover the beans with 2 inches of water and bring to a boil. Cover and remove from the heat. Let stand for 1 hour, then drain.
Cover the beans with 4 inches of fresh water. Add the sage sprig, whole garlic clove, bay leaf and 2 tablespoons of the olive oil. Bring to a boil and cook over moderately low heat for 30 minutes. Season the beans with salt and cook for about 15 minutes longer, until the beans are tender; drain and discard the sage, garlic and bay leaf.
Meanwhile, in a medium, deep skillet, heat the remaining 1/4 cup of oil. Add the chopped sage and minced garlic and cook over moderate heat for 1 minute. Add the tomato sauce and bring to a simmer.
Add the beans to the skillet and cook, stirring, until saucy and thick, 5 minutes. Season with salt and pepper and serve.